To live, deep-sea Arctic sponges feed on petrified creatures

A feast of the dead is taking place in the chilly, dark depths of the Arctic Ocean.
Researchers report in Nature Communications on February 8 that a massive colony of sponges, the densest population of these organisms seen in the Arctic, is eating the remains of an old ecosystem to live.
According to Jasper de Goeij, a deep-sea ecologist at the University of Amsterdam who was not involved with this research, the discovery demonstrates how opportunistic sponges are. Sponge evolutionarily “is more like 600 million years old, and they inhabit all sections of our world”, he said. Scientists may not be aware of all of them since many sponge habitats are difficult to access, he says.
Morganti and colleagues focused their attention in the current study on the matted layer underneath the sponge colony, which was a buffet of abandoned spicules and blackened petrified life, including empty worm tubes and mollusc shells. The scientists examined samples of sponges, mat material, and nearby water to see whether this dense mat was a food source. The researchers also looked at the genetic composition of the bacteria that dwell within the sponge tissues as well as those that live in the sediment.
Carbon and nitrogen isotopes — atoms with differing amounts of neutrons — in sponge tissues closely matched those in the dead stuff below, indicating that the creatures ate it. The bacteria’s genetic fingerprints revealed that they have enzymes capable of breaking down the substance and were most likely dissolving the dead organic stuff into food for the sponges.
The matted layer is up to 15 centimetres deep in spots, according to the experts. The team predicts that if the layer is more than 4 cm thick on average, it may give almost five times the carbon that the sponges would require to thrive.
Morganti and colleagues hypothesise that the sponge’s eating from below indicates that they are likely travelling to have access to more food. Many sponges were also discovered to be budding, or breaking off sections to generate new individuals, indicating active reproduction.
Radiocarbon dating revealed that the adult sponges, which covered more than 15 square kilometres on the peaks of an underwater volcanic mountain range, were over 300 years old on average, a “truly outstanding” discovery, according to Paco Cardenas, a sponge expert at Uppsala University in Sweden who was not involved in the new study. “We anticipated sponges to grow extremely slowly”, he adds, “but this had never been measured in the deep water”.
According to the researchers, the dead ecosystem underneath the sponges is roughly 2,000 to 3,000 years old, a once-thriving population of organisms that thrived in the nutrient-rich conditions established when the volcanoes were last active.
Sponges frequently appear to take advantage of the most plentiful carbon sources, which may change when global warming changes the makeup of the seas, according to ecologist Stephanie Archer of the Louisiana Universities Marine Consortium in Chauvin, who was not involved in the research. “One key question will be how adaptable sponge-microbe relationships are, and how rapidly they evolve to exploit new carbon sources”, she adds.

Leave a Reply

Your email address will not be published.

Back To Top